Introduction to Description Logics

Logic and Computation Courses

Introductory Course

This course provides an introduction to Description Logics (DLs) in the context of knowledge representation and reasoning (KRR). DLs are a family of logic-based KRR formalisms with interesting computational properties and many applications. In particular, DLs are well-suited for representing and reasoning about terminological knowledge and constitute the formal foundations of semantic-web ontologies. There are different flavors of description logics with specific expressive power and applications, an example of which is ALC and on which we shall have a strong focus in this course.

We start with a motivation for representing and reasoning with ontologies. We then present the description logic ALC, its syntax, semantics, logical properties and proof methods, especially the tableau-based one. Finally, we illustrate the usefulness of DLs with the popular Protégé ontology editor, a tool allowing for both the design of DL-based ontologies and the ability to perform reasoning tasks with them.